Telephone-exchange system.



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M Me- After the secon'd series of impulses have been sent out, line relay 3 remains energized and opens at its back'contact the circuit of slowacting relay lll. If the called subscribers line is idle, the test Wiper 13 of connector 5 does not find ground on the test conductor, and therefore escapement magnet 16 becomes denergized upon the opening of its circuit by slow-acting relay 14, and moves the side switch wi ers linto position 3. A circuit is now close from grounded battery, through side-switch wiper 10, conductor 20, the winding of ringing relay 21,ba`ck contact and armature of relay 22, and interrupter 23 to ground. Relay 21 interruptedly closes and opens its contacts, and connects ringing current from an alternative ringing current source 24, through front contact and armature of relay 21, sideswitch wiper 25, connector brush 11, the called subscribers line. connector brush 12, side-switch wiper 26, and the lower arma ture and front contact of relay 21, to ground. When the called subscriber at station B removes his receiver from the switchhook, or as soon thereafter as relay 21 again delinergizes. if it happens to be energized at the time, i. c., duringa silent period of-interrupter 23, o circuit is closed from ground, through side-switch wiper 15, conductor 30, rightdiand winding or relay 31. back contact and upper armature of relay 21, the called subscribes loop, lower armature and hack contact of relay 21, and left-hand winding of relay 31 to grounded battery. Relay 31 by attracting its armature, closes a circuit for a selfdocking relay 22, which upon energization opens at its back Contact the circuit of relay 21, and this relay being permanently denergized, cuts olf the ringing current from the called subscribers line. Relay 22 closes also a locking circuit for itself from grounded battery, through its Winding. front contact and right-hand armature, and front contact and armature of relay 3. to ground. Relays 22 and 31 remain energized as long as the called sul'iscriber is engaged in conversation, and relay 3 remains` energized as long as the calling subscriber A. keeps his circuit closed.

As soon as subscriber B restores his receiver to the switchhook, relay 31 becomes denergized and opens the original energizingr circuit of relay 22. Should the calling subscriber at substation A desire to resignal subscriber B, he will produce short interruptions in the circuit of line relay 3, for instance, by actuating his switchbook 27. Relay 3 upon each denergization, opens the locking circuit of relay 22, which closes at its back contact and left-hand armature the circuit of relay 21, causinglr thereby the application of ringing current to the called subscribers line B in the seme manner as above described. During the vibration of the armature of relay 3, relay 4 remains energized whereby the release of the connector is prevented.

If the called line is busythe,test wiper 13 connects a ground found on the test conductor to magnet 1G. This magnet remains energized and the side switch wipers are not .and back contacts of relays 3 and 4, oil-normal contact 36 of connector 5, and the winding of a release magnet 35 to grounded battery. Under thecontrol of magnet 35, the connector and the associated side-switch are released to normal, in which position, upon the opening of contact 36, magnet `35 becomes denergized.

1What is claimed is:

1. In a telephone exchange system, incoming lines and outgoing lines, means for extending an incoming line to an outgoing line, automatic means for signaling over said outgoing lines, means for producing short and long circuit interruptions in said incoming lines, means operation in response to said short circuit interruptions for causing the repeated operation of said automatic means, and means operative in response to said long circuit interruptions for restoring said first mentioned means.

2. In a telephone exchange system, incoming lines and outgoing lines, a selector switch for extending an incoming linel to an outgoing line, automatic means for applying interrupted signaling current to said outgoing lines, a relay associated with one end and a variably operable circuit intcrrupter with the other end of said incomingr lines, means for Causing the repeated operation of said automatic means, and means for restoringr said selector, said last two mentioned means beingr controlled by said rclav.

3. In a telephone exchange system` a plurality of substations, means for establishing a connection between a calling and frcallcd substation, a Vfull metallic circuit extending from the calling substation to said means, automatic means operative as a result of the establishment ot' the connection for signaling called substations, an interrupter for producing interruptions in said metallic circuit, and means responsive to said interruptions for causing the repeated operation of said automatic means.

4. In a telephone exchange system, a pluralitv of substations, means for establishing a connection between a calling and a called substation, a full metallic circuit extending and called substation, a full metallic circuit extending from the calling substation -to said selector, an interrupter for producing short and long interruptions in said metallic circuit, automatic means for signaling called substations, a relay adapted upon actuation to disconnect said automatic means, releasing means for said selector, another relay controlling said releasing means, means responsive to said-short interruptions for controlling said first mentioned relay and means responsive to said long interruptions for controlling said second mentioned relay.

6. In a telephone exchange system, incoming lines and outgoing lines, a selector for extending an incoming line to an outgoing line, automatic means for signaling selected outgoing lines, a self-locking r'elay controllable over a selected outgoing line for arresting the operation of said automatic means, a relay associated with said incoming line for controlling the locking circuit of said self-locking relay, a slow-acting relay controllable by said second mentioned relay, releasing means for saidselector switch operative upon the actuation of said slow-acty ing relay, a variable operable circuit interrupter associated with said incoming line, means operative upon a long interruption produced by said interi'upter for actuating said slow-acting relay, and means operative in response to short circuit interruptions produced by said interrupter to open the locking circuit of said self-locking relay and to prevent theoperation of said slow-acting relay. s'

7. In a telephone exchange system, incoming lines and outgoing lines, means for extending an incoming line to an outgoing line, automatic means for signaling over said outgoing lines, means for producing short and long circuit interruptions in said incoming lines, means operative in response to short circuit interruptions for causing the repeated operation of said automatic means,

and a disconnecting device for said first mentioned means operative in respdnse t0 said long circuit interruptions.

8. In a telephone exchange system, incoming lines and outgoing lines, a selector switch for extending an incoming line to an outgoing line, automatic means for applying interrupted signaling current to said out going lines, a relay associated with said incoming line, means for causing the repeated operation of said automatic means, and a disconnecting device for said first mentioned means, said means and device being controlled by said relay. A

9. In a telephone exchange system, a plurality of linesmeans for establishing a connection between a calling and a called line, a full metallic circuit extending from the calling line to said means, automatic means operative as a result of the establishment of the connection for signaling called lines, a.

switch for producing interruptions in said` metallic circuit, and means responsive to said interruptions for causing the repeated operation of said automatic means.

10. In a telephone exchange system, a plurality of lines, means for establishing a con nection between a calling and a called line, a full metallic circuit extending between a calling line and said means, automatic means for signaling said called line, a switchj'for producing interruptions of various duration in said metallic circuit, means responsive to interruptions of a certain duration vfor causing the operation of said automatic means, and a disconnecting device for said first mentioned means responsive to interruptions of a different duration.

11. In a telephone exchange system, a plurality of lines, means for establishing a connection between a calling and a called line, automatic means o erative as a result of the establishment o the connection for signaling called lines, a switch for producing interruptions in said calling line, and means responsive to said interruptions for causing the resignaling of called lines.

1'2. In atelephone exchange system, a plu-` rality of lines, automatic means for establishing a connection between a callin' and a called line, automatic means operative as a result of the establishment of the connection for ringing called lines, a switch 4for producing interruptions in said .calling line, and means responsive to said interruptions for vreringing called lines.

In witness whereof, I hereunto subscribe my name this 3rd day of September A. D.,

ALBEN E. LUNDELL. 

